1. Field of Invention
This invention relates to tracheostomy tubes having a curved shape, and oval or round cannulas used in the surgical instruments and accessories field for patients that have respiratory failure, respiratory tract obstructions, restrictions, lung injury and or disease.
2. Description of Prior Art
Tracheotomy has been used to assist patients who require mechanical ventilation. Tracheostomy is a common surgical procedure for intensive care patients. The goals of tracheotomy are to bypass the upper airway, facilitate removal of tracheobronchial secretions, prevent aspiration of gastric contents, and to control the airway for prolonged mechanical ventilation. Tracheostomy tubes provide life-sustaining support for patients who have obstructions, restrictions, injuries and or disease of the airway or lungs. A Physician surgically inserts a tracheostomy tube into a patient""s incision or stoma to bypass the upper airway, between the vocal cords and the bifurcation of the carina. Originally, tracheostomy tubes were made of silver such as the Jackson Tracheostomy tubes that are still produced (McPherson SP: Respiratory Care Equipment, ed 5, pp. 118-127, St. Louis, 1995, Mosby). However, metal tracheostomy tubes are difficult to clean and tarnish with time. Metal tracheostomy tubes are also expensive to make and deform or bend out of shape. Also, certain metals are irritating to the patient""s tissues. Therefore, natural rubber was used for manufacturing endotracheal tubes of the Jackson type, to U.S. Pat. No. 4,150,676 but not limited to this patent, later giving way to various types of plastics like Polyvinyl chloride (PVC). A thin surgical rubber or silicone sold under the trademark, SILASTIC of Dow Corning Corp., is also used.
Current tracheostomy tubes now come in pairs or sets, where an inner cannula is fitted into an outer cannula. There are several devices, which contain a means of locking or connecting the inner cannula to the outer cannula and the cannulas to the ventilation system. These include, but are not limited to U.S. Pat. No. 3,659,612 to Shiley et al., U.S. Pat. No. 4,009,720 to Crandall, et al., and U.S. Pat. No. 3,088,466 to Nichols. Tracheostomy tubes may remain in the airway for long periods of time, and require frequent cleaning of the inner cannula. Unfortunately, wear and tear causes problems with the means of connecting the cannulas to each other, and the ventilator circuit. The inner cannula is also manufactured separately from the set, since it tends to wear out faster than the outer cannula.
Another problem associated with tracheostomy tubes is with the balloon cuff. The first cuffs were elastic, balloon like structures that laid flat against the tube at rest. These elastic balloon cuffs had to have pressure applied from within, to actively stretch the cuff until it pressed against the airway to make a seal. This type of cuff is referred to as a low-residual-volume, high-pressure cuff. Because cuffs of this type tend to cause sufficient pressure on the respiratory tract mucosa of the trachea to stop capillary blood flow, maneuvers such as the minimal leak technique are use. In this technique a slight leak during inhalation is allowed around the cuff, for patients receiving long-term mechanically supported ventilation. When just enough volume is used to occlude the airway, the technique is referred to as the minimal occluding volume. Periodic deflation of the cuff every hour for 5 minutes has also been used, although the adequacy of this technique has been questioned. These methods have been devise to try to minimize the potential of tracheal wall dilation, and mucosal necrosis with long-term use of cuffed tubes (Scanlan C L., et al: Egan""s Fundamentals of Respiratory Care, pp. 540-580, ed 6. St. Louis, 1995, Mosby).
Reducing the potential of necrosis also prompted the development of other types of cuff designs with high-residual-volume and low pressure. These cuffs are larger that high-pressure cuffs and are actively deflated for insertion, then partially inflated with enough air to obtain a seal against the tracheal wall. Low-volume, high-pressure cuffs may exert less than 25 mmHg. Examples of tubes incorporating the newer low-pressure designs are sold under the trademark SOFT-CUF by Forreger Company, Inc., and the trademark SOFT-SEAL by Portex Limited Company. Shiley et al., also makes a tube with a cuff that has a relatively large residual volume. Shiley et al""s cuff is cylindrical in shape, is made of comparatively rigid material, and is also said to inflate evenly. Tracheostomy tubes disclosed in U.S. Pat. No. 3,659,612 to Shiley et al., and U.S. Pat. No. 4,009,720 to Crandall shows a similar cuff mechanism including a pilot tube attached to a balloon, which is inserted within the airway located on the outer cannula. There are other examples of balloon cuffs and regulating valves, etc., and the above should be considered as examples or illustrative and should not be considered limiting to the particular forms shown.
When the tracheostomy tube is placed into the stoma, the balloon cuff is placed between the vocal cords and the carina. Once the cuff gets worn or has too much air added into it, the cuff is damaged and must be replaced. This entails removal of the outer cannula, in order to replace the balloon cuff. Irritation, pain and or bleeding can also occur to the patient""s stoma site during the cuff replacement procedure. The current procedure for balloon cuff replacement also entails the removal of the retaining strap that is attached to the flange on the outer cannula. This cord holds the tracheostomy tubes in place around the patients"" neck. One type of strap or cord for supporting tracheostomy tubes is described in U.S. Pat. No. 4,331,144 to Wapner, and there are others as well.
La Rosa in U.S. Pat. No. 4,033,353 describes but is not limited to a neck flange made of a flexible material to which a tracheostomy tube is mounted by flexible portions thereof Flanges and straps irritate the patient""s neck, causing discomfort, redness and rashes to occur to the surrounding outer neck area.
Current tracheostomy tubes having long outer cannulas can cause a condition where the trachea is irritated, and a hole (tracheoesophageal fistula) forms in the posterior wall adjoining the esophagus. Other tracheal lesions that occur are tracheal granulomas, tracheomalacia, and tracheal stenosis. Tracheal granulomas usually form in the trachea near the tracheal tube tip. They are probably related to tube movement. Another site of granulomas development is the tracheal stoma itself This may be due to a foreign body reaction. Tracheomalacia and tracheal stenosis occur either separately or together. Tracheomalacia is the softening of the cartilaginous rings, which causes collapse of the trachea during inspiration. Processes similar to those causing mucosal ulceration may lead to debridement of the epithelium, and exposure and necrosis of the tracheal rings. The extent of tracheomalacia depends on the degree of damage to the cartilage. In patients with tracheostomy tubes, stenosis may occur either at the cuff site or at the tip of the tube. Stenosis at the stoma site is more common. Typically, stenosis at the stoma occurs when the sides of the incision pull together during healing. Usually the posterior wall of the trachea is unaffected. Stenosis at the stoma site may be caused by too large a stoma, infection of the stoma, movement of the tube, or frequent tube changes (McPherson S P: Respiratory Care Equipment, ed 5, pp. 118-127, St. Louis, 1995, Mosby).
Artificial airways are fundamentally simple devices designed to provide the patient with a patent airway, reduce the work of breathing, enhance clearance of pulmonary secretions, and provide a route for the administration of ventilatory assistance or control. It is an important requirement that tracheostomy tubes provide an air supply to the patient, while minimizing their discomfort. Practitioners must use the proper equipment and procedure with sound techniques of airway management and maintenance, in order to minimize the possibility of serious complications to the patient""s airway.
Objects and Advantages
From the description above, a number of objects and advantages of my tracheostomy tube become evident:
a) Accordingly, the main object and advantage in my tracheostomy tube is to provide an improved tracheostomy tube in which aforementioned disadvantages will be decreased.
b) Another object and advantage to my tracheostomy tube to improve the safety and reduce the possible chances for serious complications.
c) Still another object and advantage in my design is to prevent and or reduce tracheoesophageal fistulas from developing and or healing if already present.
d) It is also another object and advantage in my tracheostomy tube design to help seal and prevent secretions from accumulating between the outer and inner cannulas.
e) An additional object and advantage in my tracheostomy tube is that the outer and inner cannulas can be attached or mated for added security.
f) A further object and advantage in my tracheostomy tube is to make it lighter and stronger.
g) Yet another object and advantage in my tracheostomy tube is that the replaceable inner cannula design will make it easier to replace the balloon cuff.
h) A extra object and advantage in my tracheostomy tube is to provide the patient with a more comfortable tracheostomy tube.
i) It is a further object and advantage that my tracheostomy tube provides an easier replacement procedure for the health care practitioners, when removing the balloon cuff.
Further objects and advantages with my Tracheostomy tube will become apparent from a consideration of the drawings and ensuing description, which will reinforce and affirm my invention.
In accordance with the present invention an improved tracheostomy tube comprises a balloon cuff, balloon connector, guide balloon valve, and guide balloon located on the inner cannula and inserted into a shorter uncuffed outer cannula. When the tracheostomy tube set is inserted in the tracheal stoma, the set will be held in place by means of a strap wrapped around the patient""s neck and attached to eyelet""s located on the outer cannula retainer.